Two dimension layout and point transfer system

ABSTRACT

A two-dimension layout system identifies points and their coordinates, and transfers identified points on a solid surface to other surfaces in a vertical direction. Two leveling laser light transmitters are used with a remote unit to control certain functions. The laser transmitters rotate about the azimuth, and emit vertical (plumb) laser planes. After being set up using benchmark points, the projected lines of the laser planes will intersect on the floor of a jobsite at any point of interest in a virtual floor plan, under control of a user with the remote unit. The laser light planes also project lines that will intersect along the ceiling at a point that is truly plumb above the crossing point on the floor. The laser planes also provide an “implied” plumb line that is projected in space, which is visible along a solid vertical surface to between the intersecting floor and ceiling points.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of application Ser. No.12/824,716, titled “TWO DIMENSION LAYOUT AND POINT TRANSFER SYSTEM,”filed on Jun. 28, 2010.

TECHNICAL FIELD

The technology disclosed herein relates generally to layout “surveying”equipment and is particularly directed to a two-dimension layout systemof the type which identifies points and their coordinates, and transfersidentified points on a surface to other surfaces in a verticaldirection. Embodiments are specifically disclosed using two laser lighttransmitters with a remote unit to control certain functions. The lasertransmitters may be identical. Preferably the laser transmitters includea self-leveling capability, and exhibit a rotation about the azimuth,and a vertical (plumb) laser plane (or rotating line) output. When thesystem is set up it is capable of aiming (by rotation) each of thevertical (laser light) plane outputs from the transmitters (which arepositioned at some distance apart), so that the projected lines (of thelaser light planes) will cross on the surface at any given desired pointon the jobsite. In addition, the extent (divergence) of the projectedlaser light planes are such that they also cross overhead on theceiling, which crossing point occurs at a location that is truly plumbabove the corresponding crossing point on the surface. A further featureof the system provides an “implied” plumb line that is projected inspace, and is represented by the intersection of the two planes betweenthe point intersections on the surface and the ceiling. This impliedplumb line is visible if a solid surface (or perhaps smoke) is placed inthe volumetric space where the plumb line is projected. The systemincludes a methodology for simplified layout and direct point transferto the ceiling.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

None.

BACKGROUND

The present invention relates generally to a laser system that providesthe elements for visually locating points of interest on atwo-dimensional horizontal surface for use in primarily interiorconstruction environments. A simple, accurate and cost effective systemfor the layout of floor plans at the jobsite has long been in need.Conventional GPS is not usable inside standard steel constructionbuildings. Previous laser based systems have been overly complex andexpensive, missing the mark in almost every area required for thismarket.

In prior art laser based positioning systems, such as disclosed in U.S.Pat. No. 5,100,229, three or more laser transmitters (beacons) areplaced around the perimeter of a work site. Each transmitter emits aplane of light approximately 45 degrees to vertical while continuouslyrotating at a constant speed. The beams from each transmitter must eachhave their own unique and highly controlled speed of rotation, oralternatively their own unique modulation frequency, so they may bedistinguished from each other. A strobe on each provides a referencesignal to start a series of timing events that are ultimately utilizedto triangulate position. The system can be used for two-dimensional orthree-dimensional applications. The complexity of this method is veryhigh, and the requirement of having constant rotational laser scanningis critical. In addition, it is computationally intensive, especiallywhen setting up the system.

Another prior apparatus, such as disclosed in U.S. Pat. No. 5,076,690,uses a rotating laser beam to scan retro-reflective bar coded targetsplaced around the perimeter of the job site. The portabletransmitter/receiver utilizes optical collection optics to receive theretro-reflected energy from at least three of the targets. A rotationalencoder assumes a relatively constant rotation speed and interpolatesbetween each perimeter slot of the encoder disk a precision azimuthangle for each acquired target. After a set-up procedure that uses atleast two known benchmarks, the working field is ‘scaled’ so that anyother point of interest can be found with a two-dimensional workingplane. A complex method to precision calibrate and characterize eachleading edge of each rotary encoder slot is required to provide thelevel of precision sought in the construction layout application. Jobsite obstructions also become a challenge when acquiring sufficienttargets in the right place, with respect to the position of thetransmitter, to provide a strong calculation of position.

Still another method of laser based positioning is disclosed in U.S.Pat. No. 7,110,092. Two parallel laser beams are emitted at a knowndistance from each other. The beams are rotated together at a constantspeed, thus defining the working plane. A laser receiver is used todetermine when each beam becomes incident on the sensing element.Because the rotation of the beams is assumed to be constant, the timingof the two beams incident on the receiver becomes faster at greaterdistances and thus is a smaller percentage of the time it takes totraverse the entire perimeter. Distance is extrapolated from thisinformation. Further, if an index is provided to indicate the start ofrotation of the laser beams, then position can be found. Constantrotation speed is again very critical, and the position calculation forthis method typically has not been sufficient accuracy for what isrequired for typical construction jobsite layout.

Still other laser based methods have been used to provide theconstruction layout function. Several of them, such as thosemanufactured and marketed by SL Laser and Flexijet, utilize a pointinglaser beam that is mounted on a rotating base that can provide azimuthangle and a frame with a rotatable sextant that can provide altitudeangle. In this manner a laser beam can be pointed in the direction of adesired point of interest and projected onto a surface. The indicatedpoint location is accurate only if the surface onto which it isprojected is both flat and at the theoretically expected elevation.Otherwise serious errors can occur, and become increasingly large as theincident projection angle onto the surface becomes steeper.

It is seen that there remains a need for a more effective positioningsystem for use in the construction industry and, more specifically, forfloor layout indoors. This need encompasses the desire for moresimplicity so that its concept of operation and method of use is muchmore intuitive to the user. Set up of the system should bestraightforward and fast. In addition, there is a need to provide avisual system for interior use. Doing so will add to the intuitivenature of the system as well as reduce the overall expense of thesystem, because the function of automatically detecting an encoded ormodulated laser signal is not required. Lastly, there is a need toprovide a system where the projection onto a surface is not subject toflatness errors of the incident surface.

SUMMARY

Accordingly, it is an advantage to provide a floor layout system thatincludes two base units that can have an alignment axis establishedtherebetween, and a remote unit that communicates with both of the baseunits, in which the system is configured to provide a visualpresentation of virtual points on a jobsite physical surface that havepredetermined coordinates, relative to locations of at least twobenchmark points.

It is another advantage to provide a base unit that has a lasertransmitter having an optical emission that creates a vertical laserlight plane, a laser receiver with a null position-detecting capability,in which the receiver is mounted to detect laser light offsets in thehorizontal direction, and a leveling mechanism.

It is yet another advantage to provide a remote unit that has a computerprocessing circuit and a memory circuit, along with a communicationcircuit that can communicate to at least one base unit of a floor layoutsystem, in which the remote unit also has a display and a usercontrolled input device; the remote unit also is in communication with avirtual building plan, and its display is capable of depicting at leasttwo benchmark points and at least one known virtual point that is to bevisually indicated on a jobsite physical surface.

It is still another advantage to provide a method for setting up a floorlayout system, in which the system includes two base units each having alaser transmitter, wherein a user will perform certain functions on ajobsite, including: (a) positioning the two base units on a jobsitefloor, (b) aligning the two laser transmitters of both base units tocreate an alignment axis, (c) locating two benchmark points withintersecting laser light from the two laser transmitters, and (d)determining azimuth angles of the two laser transmitters for thosebenchmark points.

It is a further advantage to provide a method for using a floor layoutsystem having “known” points of a building plan, in which the systemincludes two base units each with a laser transmitter, and including aremote unit that is communication with the base units; wherein a userperforms certain functions, including: (a) positioning the two lasertransmitters of the base units on a jobsite floor to establish analignment axis therebetween, (b) providing a virtual jobsite floor plan,(c) determining coordinates of two benchmark points of the virtual floorplan and determining azimuth angles of the two laser transmitterscorresponding to those benchmark points, (d) entering coordinates for apoint of interest on the virtual floor plan, and slewing the two lasertransmitters to those coordinates, and (e) visually indicating thephysical point of interest on the jobsite floor, by use the laser lightlines produced by the laser transmitters.

It is yet a further advantage to provide a method for using a floorlayout system to enter “unknown” points of a jobsite into a virtualfloor plan, in which a system has two base units each with a lasertransmitter, and a remote unit that is in communication with the baseunits; wherein a user performs certain functions, including: (a)positioning the two laser transmitters of the base units on a jobsitefloor to establish an alignment axis therebetween, (b) providing avirtual jobsite floor plan, (c) determining coordinates of two benchmarkpoints of the virtual floor plan and determining azimuth angles of thetwo laser transmitters corresponding to those benchmark points, (d)selecting an “unknown” physical point of interest on the jobsite floor,(e) slewing the two laser transmitters so that they create visibleintersecting light lines at that physical point of interest, (f)entering the azimuth angles for the two laser transmitters to determinethe corresponding coordinates of that point of interest on the remoteunit, and (g) using reverse calculations, plotting that physical pointof interest on the virtual floor plan of the remote unit.

Additional advantages and other novel features will be set forth in partin the description that follows and in part will become apparent tothose skilled in the art upon examination of the following or may belearned with the practice of the technology disclosed herein.

To achieve the foregoing and other advantages, and in accordance withone aspect, a layout and point transfer system is provided, whichcomprises: (a) a first base unit, having a first laser light transmitterthat emits a first laser light plane, and a first processing circuit;and (b) a second base unit, having a second laser light transmitter thatemits a second laser light plane, and a second processing circuit;wherein: (c) the system is configured to register locations of the firstand second base units on a physical jobsite surface with respect to atleast two benchmark points that are also located on the physical jobsitesurface; and (d) the system is configured to provide a visualrepresentation of a virtual point on the physical jobsite surface, byaiming first laser light plane and the second laser light plane, toindicate a location of the virtual point.

In accordance with another aspect, a base unit for use in a floor layoutand point transfer system is provided, which comprises: a first laserlight transmitter that emits a substantially vertical plane of laserlight, the first laser light transmitter being rotatable about asubstantially vertical axis; a laser light receiver having: anull-position photosensor that is mounted to detect laser light offsetsin a substantially horizontal direction, and an amplifier circuitinterfacing between the null-position photosensor and the laser lightreceiver; and a leveling mechanism.

In accordance with yet another aspect a method for setting up a layoutand point transfer system is provided, in which the method comprises thefollowing steps: (a) providing a first base unit which includes a firstlaser light transmitter that emits a first laser light plane; (b)providing a second base unit which includes a second laser lighttransmitter that emits a second laser light plane; (c) positioning thefirst base unit and the second base unit at two different locations on asolid surface of a jobsite; (d) determining an alignment axis betweenthe first base unit and the second base unit; (e) aiming the first laserlight transmitter and the second laser light transmitter so that a firstbenchmark point is indicated by intersecting laser light lines along thesolid surface, which are produced by the first and second laser lightplanes; and determining a first set of azimuth angles of the first andsecond laser light transmitters; (f) aiming the first laser lighttransmitter and the second laser light transmitter so that a secondbenchmark point is indicated by intersecting laser light lines along thesolid surface, which are produced by the first and second laser lightplanes; and determining a second set of azimuth angles of the first andsecond laser light transmitters; and (g) by use of the first and secondsets of azimuth angles, determining positions of the first and secondbase units with respect to the first and second benchmark points.

Still other advantages will become apparent to those skilled in this artfrom the following description and drawings wherein there is describedand shown a preferred embodiment in one of the best modes contemplatedfor carrying out the technology. As will be realized, the technologydisclosed herein is capable of other different embodiments, and itsseveral details are capable of modification in various, obvious aspectsall without departing from its principles. Accordingly, the drawings anddescriptions will be regarded as illustrative in nature and not asrestrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of thespecification illustrate several aspects of the technology disclosedherein, and together with the description and claims serve to explainthe principles of the technology. In the drawings:

FIG. 1 is a block diagram of the major components of a layout and pointtransfer system, as constructed according the principles of thetechnology disclosed herein.

FIG. 2 is a block diagram of the major components of a laser transmitterthat is part of a base unit depicted in FIG. 1.

FIG. 3 is a block diagram of the major components of a laser receiverthat is part of a base unit that is depicted in FIG. 1.

FIG. 4 is a block diagram of the major components of a remote unit thatis part of the system of FIG. 1.

FIG. 5 is a flow chart of the steps performed by a system set-uproutine, for the system depicted in FIG. 1.

FIG. 6 is a flow chart of the steps performed by a routine to find a“known” point on a floor layout plan, using the system of FIG. 1.

FIG. 7 is a flow chart of the steps performed by a routine to enter an“unknown” point on a jobsite, using the system of FIG. 1.

FIG. 8 is a diagrammatic view of an “automatic” base unit, as used inthe system of FIG. 1.

FIGS. 9-13 are diagrammatic views of how a human user would use thesystem of FIG. 1, first to align a pair of transmitter axes, then toalign the transmitters to two different benchmark points, then to alignthe laser planes to a floor point, and finally to align the laser planesalong a plumb line of a wall surface.

FIGS. 14-19 are diagrammatic views showing how two base units of thesystem of FIG. 1 can automatically establish an alignment axistherebetween.

FIG. 20 is an elevational view of a conventional laser position pointingsystem that is known in the prior art, depicting its attempt to projecta position of a point of interest on an uneven jobsite floor.

FIG. 21 is an elevational view of the system of FIG. 1, showing two baseunits with laser transmitters that correctly project a position of apoint of interest on an uneven jobsite floor.

FIG. 22 is a diagram showing positions of physical points and anglesinvolved in a set-up routine.

FIG. 23 is a diagram showing positions of physical points and anglesinvolved in a routine for locating a known point of interest.

FIG. 24 is a diagram showing positions of physical points and anglesinvolved in a routine for entering an unknown point of interest.

DETAILED DESCRIPTION

Reference will now be made in detail to the present preferredembodiment, an example of which is illustrated in the accompanyingdrawings, wherein like numerals indicate the same elements throughoutthe views.

It is to be understood that the technology disclosed herein is notlimited in its application to the details of construction and thearrangement of components set forth in the following description orillustrated in the drawings. The technology disclosed herein is capableof other embodiments and of being practiced or of being carried out invarious ways. Also, it is to be understood that the phraseology andterminology used herein is for the purpose of description and should notbe regarded as limiting. The use of “including,” “comprising,” or“having” and variations thereof herein is meant to encompass the itemslisted thereafter and equivalents thereof as well as additional items.Unless limited otherwise, the terms “connected,” “coupled,” and“mounted,” and variations thereof herein are used broadly and encompassdirect and indirect connections, couplings, and mountings. In addition,the terms “connected” and “coupled” and variations thereof are notrestricted to physical or mechanical connections or couplings.

In addition, it should be understood that embodiments disclosed hereininclude both hardware and electronic components or modules that, forpurposes of discussion, may be illustrated and described as if themajority of the components were implemented solely in hardware.

However, one of ordinary skill in the art, and based on a reading ofthis detailed description, would recognize that, in at least oneembodiment, the electronic based aspects of the technology disclosedherein may be implemented in software. As such, it should be noted thata plurality of hardware and software-based devices, as well as aplurality of different structural components may be utilized toimplement the technology disclosed herein.

It will be understood that the term “circuit” as used herein canrepresent an actual electronic circuit, such as an integrated circuitchip (or a portion thereof), or it can represent a function that isperformed by a processing device, such as a microprocessor or an ASICthat includes a logic state machine or another form of processingelement (including a sequential processing device). A specific type ofcircuit could be an analog circuit or a digital circuit of some type,although such a circuit possibly could be implemented in software by alogic state machine or a sequential processor. In other words, if aprocessing circuit is used to perform a desired function used in thetechnology disclosed herein (such as a demodulation function), thenthere might not be a specific “circuit” that could be called a“demodulation circuit;” however, there would be a demodulation“function” that is performed by the software. All of these possibilitiesare contemplated by the inventors, and are within the principles of thetechnology when discussing a “circuit.”

System Set-Up; Introduction

It is assumed that there exists at least two known points (alsosometimes referred to as “benchmarks” herein) on the jobsite which canbe utilized for the setting up the system. These benchmark points wouldhave been established from previous survey efforts. FIGS. 9-11illustrate a basic example of how the system can be set up. A first step(see FIG. 9) illustrates an alignment of the transmitters' outputvertical planes to each other with the use of an RF (radio frequency)remote unit. This establishes an axis between the centerlines of eachtransmitter “base unit” device and indexes the angular encoders to that.This process can be performed by visually aligning the transmitterplanes to each other, but may be facilitated with the addition of asplit photocell on the transmitter base units that would guide and lockinto place the respective planes, adding convenience and precision tothe process.

A second step (see FIG. 10) illustrates the establishment of the firstknown benchmark. The vertical planes from each transmitter base unit arecommanded to position over the point of interest by the handheld radioremote unit, and then their coordinates are entered. The second knownbenchmark is entered in a similar manner, in a third step (asillustrated in FIG. 11). After this third step, the remote unit'scomputer system has sufficient set-up information to calculate thelocation and “find” any other point of interest within the working area.The above example steps will be discussed below, in greater detail.

Finding a “Known” Point; Introduction

FIG. 12 illustrates a basic configuration of laser transmitters andoutput laser plane configurations for a system that was previouslyset-up. The vertical laser light planes emitted by the base unit lasertransmitters can be visible red laser light; however, other lightwavelengths could be used instead, such as infrared, green, or otherlight wavelengths as well. For many of the applications using thissystem, it will be preferable for the laser light to be of a visiblewavelength, and the description hereinbelow will assume that is thecase.

The laser planes emanate from the two laser transmitters' rotors, whichhave capability of rotation about the vertical instrument axis. Thisallows each laser transmitter the ability to position its visiblevertical plane at any angle about its rotation axis, and then to holdstatic at that position. The laser transmitters are located at adistance (not necessarily known) from each other; in this example, theyare positioned near each corner of the room. As can be seen from FIG.12, a first point is formed on the floor at the intersection of the twolaser planes. In addition, a second point is formed on the ceiling,above the first point on the floor. If the two laser planes are trulyvertical with respect to gravity, then the point on the ceiling is in alocation that is plumbed over the point on the floor. Anotherinteresting aspect is the formation of an implied plumb line where thetwo laser planes intersect.

When the system is set up on a jobsite, the laser planes can becommanded to rotate into position so that the intersection identifiesany point of interest (on the floor or ceiling) that the user chooses.This is accomplished via the remote unit (using, for example, a radiolink or an IR link) that communicates with the two base unit lasertransmitters, thereby allowing the user mobility throughout the room andenabling him/her to be at the physical location where the layout work isbeing performed.

Once the set-up is completed the user may enter coordinates of interestinto the handheld remote unit. When this occurs each vertical laserplane can be commanded to slew into position so that the visibleintersection will reveal the physical location. Points of interest mayalso be downloaded from other support software so that the user cansimply choose various points of interest from a listing. Floor layoutcan proceed accordingly. Because there exists a “second” intersection onthe ceiling that is continuously plumbed over the “first” intersectionon the floor, point transfer from floor to ceiling can proceedsimultaneously. This is of use in laying out sprinkler systems and thelike. In addition, there is a vertical implied plumb line at theintersection of the two vertical planes (i.e., between the two floor andceiling intersection points). This vertical implied plumb line can beused to help align and set studded walls—an example of this methodologyis illustrated in FIG. 13. These examples will be discussed below, ingreater detail.

Details of System Hardware

Referring now to FIG. 1, an entire layout and point transfer system,generally designated by the reference numeral 10, is depicted in blockdiagram form. A first base unit is generally designated by the referencenumeral 20, and is also referred to on FIG. 1 as “BASE UNIT #A.” Asecond base unit is generally designated by the reference numeral 30,and is also referred to on FIG. 1 as “BASE UNIT #B.”

Base unit 20 includes a laser transmitter “T1,” at reference numeral 22.Laser transmitter 22 includes a processing circuit, a memory circuit, aninput/output circuit, a laser light source, and a leveling platform.

Base unit 20 contains a laser receiver “R1,” in a preferred mode of thissystem. This laser receiver is also designated by the reference numeral24, and includes a processing circuit, a memory circuit, an input/outputcircuit, and at least one photosensor. Different configurations ofphotosensors can be used for this laser receiver, as discussed below ingreater detail.

Base unit 20 further includes an aiming platform “A1,” which isdesignated by the reference numeral 26. This aiming platform includes anangle encoder, and an angle drive circuit. This aiming platform 26 willbe described in greater detail below.

Base unit 30 includes a laser transmitter, in this instance referred toas “T2,” and designated by the reference numeral 32. Laser transmitter32 also includes a processing circuit, memory circuit, input/outputcircuit, laser light source, and a leveling platform.

Base unit 30 also includes a laser receiver referred to as “R2,” andgenerally designated by the reference numeral 34. This laser receiveralso includes a processing circuit, memory circuit, input/out circuit,and photosensors.

Base unit 30 also includes an aiming platform, referred to as “A2,” andgenerally designated by the reference numeral 36. This second aimingplatform includes an angle encoder, and an angle drive circuit. Theseare similar to the same types of devices in the aiming platform 26, andwill be discussed below in greater detail.

The system 10 also includes a remote unit, which is generally designatedby the reference numeral 40 on FIG. 1. Remote unit 40 includes aprocessing circuit, a memory circuit, an input/out circuit, a display,and a keypad. Alternatively, remote unit 40 could include a touch screendisplay which would incorporate the main functions of a keypad, withouthaving a separate keypad on the unit. The memory circuit of remote unit40 can have two components: a first internal component, and either anexternal component or a “bulk memory” component, which is designated bythe reference numeral 42 on FIG. 1. The external characteristic ofmemory circuit 42 could be comprised of a flash memory or other type ofportable memory device, such as a “stick ROM.” Such a portable memorydevice could be carried by a user, and could be plugged into a port ofthe remote unit 40, if desired. This will be discussed in greater detailbelow.

Another possible component of system 10 is a computer generallydesignated by the reference numeral 50. This computer is referred to asan “ARCHITECT COMPUTER,” on FIG. 1. Although the owner of computer 50may or may not truly be an architect, for the purposes of thisdescription, it will be assumed that computer 50 includes floor plans orsome other type of computer files that were either created or used by anarchitect, or by some type of building engineer. This assumes that thesystem 10 is going to be used on a jobsite in which a building will beconstructed. Of course, other types of structures or perhaps highwayscan use the technology disclosed herein, and such a jobsite may not haveany type of enclosed building structure at all.

The computer 50 includes a processing circuit, a memory circuit, and aninput/output circuit. The memory circuit of computer 50 will eithercontain floor plans (designated at 54), or some other type of computerfiles such as computer-aided drafting (CAD) files at 52, on FIG. 1. Itshould be noted that the remote unit 40 itself could have some type ofcomputer-aided architecture or CAD software installed thereon (dependingon how “powerful” the computer/memory system is for the remote unit),and in that event, the virtual floor plan could also be directlycontained in memory circuit 42, and displayed in two, or perhaps eventhree dimensions.

It will be understood that all of the main units illustrated on FIG. 1include some type of input/output circuit, and these types of circuitsinclude communications circuits. Such communication circuits possiblycould be plug-in ports, such as USB ports; moreover, such input/outputcircuits also can include wireless communications circuits, such as lowpower radio-frequency transmitters and receivers, or other types ofwireless communications ports that use other wavelengths, such asinfrared light, for transmitting and receiving data between the variousunits. This type of technology is already available today, althoughcertainly there will be newer forms invented in the future, that canstill be used in the system 10 of FIG. 1.

Referring now to FIG. 2, a block diagram of a laser transmitter used inone of the base units is illustrated, and is generally designated by thereference numeral 100. Laser transmitter 100 includes a processingcircuit 110, which will have associated random access memory (RAM) at112, associated read only memory (ROM) at 114, and at least oneinput/output circuit at 116. These devices 112, 114, and 116 communicatewith the processing circuit 110 by use of a bus 118, which typically isreferred to as an address bus or a data bus, and can also contain othertypes of signals, such as interrupts and perhaps other types of timingsignals.

The input/output circuit 116 will sometimes also be referred to hereinas an I/O circuit. This I/O circuit 116 is a primary interface betweenthe real world devices and the processing circuit 110. It is incommunication with various communications devices and also various typesof motor drive circuits and sensor circuits.

The input/output circuit 116 is in communication with a communicationsport A, which is generally designated by the reference numeral 120.Communications port 120 includes a transmitter circuit 122 and receivercircuit 124. Communications port 120 is provided to exchange datainformation with the remote unit 40, which on FIG. 2 is referred to asthe remote unit 300. The communication link between remote unit 300 andcommunications port 120 is designated by the reference numeral 126. In apreferred mode of this system, the communication link 126 will bewireless, although certainly a cable could be connected between thecommunications port 120 and the remote unit 300, if desired.

A second communications port, referred to as port B is generallydesignated by the reference numeral 130 on FIG. 2. This port 130comprises a data interface with an input circuit at 132 and outputcircuit at 134. Communications port 130 transfers data to and from anull-position photosensor, generally designated by the reference numeral200, using a communication path 136. While it would be possible forcommunication link 136 to be wireless, there is no particular need forthat to be so. The null-position photosensor 200 will typically bemounted directly on the base unit, as will be the laser transmitter 100.Therefore, a direct “wired” link will be typical.

Laser transmitter 100 also includes a leveling motor drive circuit,generally designated by the reference numeral 140. This drive circuitprovides the voltage and current for a leveling motor 142. In addition,it receives signals from a level sensor 144, and these input signalswill determine what types of commands will be sent to the motor 142 fromthe drive circuit 140. If desired, this can be a self-contained systemthat may not need to communicate with the processing circuit 110.However, the laser transmitter 100 will typically desire knowledge ofwhether or not the base unit has actually finished its leveling functionbefore the laser transmitter 100 begins to function in its normal modeof operation. In addition, the processing circuit 110 may well desire tocontrol the leveling motor drive circuit 140, essentially to keep itde-energized at times when it is not critical for the base unit toactually be attempting to level itself with respect to gravity.

Laser transmitter 100 also includes an angle encoder 150, in a preferredembodiment. Angle encoder 150 will provide input signals to theprocessing circuit 110, so that it knows exactly where the lasertransmitter is being pointed with respect to the azimuth direction. Thiscould be a wholly manual operation, if desired to reduce system cost byeliminating the encoder. However, for a fully automated system, theangle encoder 150 will be necessary.

Laser transmitter 100 preferable will also include an azimuth motordrive, generally designated by the reference numeral 160. Motor drive160 will provide the proper current and voltage to drive the azimuthmotor 162, which is the motive force to aim the laser transmitter. Thisagain could be part of a self-contained system, working with the angleencoder 150; however, on FIG. 2, it is illustrated as being controlledby the processing circuit 110.

Laser transmitter 100 also includes a laser light source driver circuit170, which provides the current and voltage to drive a laser lightsource 172. This typically will be a laser diode, although it could bean other type of laser light beam emitter, if desired. As describedabove, the laser light source will typically be emitting visible light,although a non-visible light source could be desirable for certainapplications, and a laser light source emitting infrared light could beused in that situation. The laser source driver 170 is controlled byprocessing circuit 110 in the configuration illustrated on FIG. 2.

The laser transmitter 100 will typically be a “fan beam” lasertransmitter for use in the system 10. However, it will be understoodthat other types of laser light sources could be used, including arotating laser beam, if desired. However, there must be some minimumamount of divergence to create a laser light “plane” so that the laserlight will at least intersect the floor surface of a jobsite, andpreferably also intersect a ceiling surface for enclosed spaces onjobsites. The system 10 will have many uses, even if the laser lightsource only is pointing at a floor surface, but system 10 expands itsusefulness if the divergence angle of the laser plane is designed tointersect not only the floor, but also the ceiling of the enclosedspace. In this description, it will be assumed that the laser lightsource is a fan beam laser, and so a continuous plane of laser light isbeing emitted by each laser transmitter 100 at both base units 20 and30.

Referring now to FIG. 3, a laser receiver generally designated by thereference numeral 200 is depicted in block diagram form. Laser receiver200 includes a processing circuit 210, which has associated RAM 212, ROM214, and an input/output interface circuit 216. These devicescommunication with the processing circuit 210 over a bus 218, typicallyincluding at least data and address lines.

The input/output circuit 216 receives signals from some type ofphotosensor. On FIG. 3 two different types of photosensors are depicted.A “butt end” photosensor is depicted at the reference numeral 220, andthis assumes there are only two individual photocells. Each of thesephotocells of the photosensor 220 provides an electrical signal to again stage 222. The output of the gain stage is directed to ademodulation circuit 224, and the output of that circuit directs asignal to the I/O circuit 216. It will be understood that a demodulationcircuit will not be necessary unless the laser light signals themselvesare of a modulated type of signal. In most applications for the system10, a modulated laser light signal will be desirable, and thus ademodulation circuit 224 will be used in those instances.

The second type of photosensor is depicted as a portion of what issometimes referred to as a “rod sensor” and is designated by thereference numeral 230. An exemplary “full” rod sensor is disclosed inU.S. Pat. No. 7,110,092, which issued on Sep. 19, 2006, which disclosureis incorporated by reference herein in its entirety. It will beunderstood that the second photosensor 230 can comprise virtually anytype of “all-around” light-sensing device, i.e., a photosensor that isable to detect incoming light from essentially any angle.

A typical “full” rod sensor would have two photocells, one at each endof the light-conducting rod. However, rod sensor 230 has only a singlephotocell in FIG. 3, which produces an electrical signal that isdirected to a gain stage 232, which outputs a signal to a demodulationstage 234. As in the other type of photosensor circuit described above,the demodulation circuit 234 is only necessary if the laser light sourceemits a modulated signal, which would be typical for this system 10.

An interface circuit 240 is also provided in the laser receiver 200.This is a separate interface circuit from the I/O circuit 216. Interfacecircuit 240 communicates position information to the laser transmittercommunications port B, which will be used in helping “aim” the lasertransmitters during a portion of the set-up mode of operation, asdiscussed below.

Referring now to FIG. 4, a block diagram is provided for a remote unit,which is generally designated by the reference numeral 300. Remote unit300 includes a processing circuit 310, with associated RAM 312, ROM 314,some type of bulk memory or external memory 316, and an input/outputcircuit 318. These circuits are all in communication with the processingcircuit 310 via a bus 315, which normally would carry data signals andaddress signals, and other types of microprocessor signals, such asinterrupts.

The bulk memory 316 could be a disk drive, or perhaps some type of flashmemory. If in the form of flash memory, it could be an external memorydevice (such as a “portable memory device”) that can plug into theremote unit, via a USB port, for example. In that situation, there wouldbe a USB interface between the bulk memory device 316 and the bus 315.

The I/O circuit 318 will be in communication with a first communicationsport 320, which is designated as communications port “X” on FIG. 4.Communications port 320 includes a transmitter circuit 322, and areceiver circuit 324. Communications port 320 is designed tocommunication with the base units 20 and 30, typically using a wirelesssignal via a wireless pathway 326 (as noted on FIG. 4). As described ingreater detail below, the base units 20 and 30 will communicate azimuthangular information with the remote unit, and that information arrivesvia the wireless path 326 to and from communications port 320.

A second communications port 330 is included in remote unit 300, andthis is designated as communications port “Y” on FIG. 4. Communicationsport 330 includes a transmitter circuit 322 and receiver circuit 334.This communications port 330 is provided to exchange information withthe architect computer 50, via a communication link 336. On FIG. 4,communication link 336 is depicted as a wireless link, although itcertainly could be constructed by use of an electrical cable or anoptical cable, if desired. Communications port 330 will exchange floorlayout data with the architect computer 50; more specifically, it canreceive a floor plan and store it in the bulk memory circuit 316. Inaddition, if the remote unit 300 receives information about a new or“unknown” point of interest in the physical jobsite floor plan, thenthat information can not only be saved in the bulk memory circuit 316,but could be also communicated back to the architect computer 50, viathe communications port 330 to be placed in the original floor plan. Or,a revised floor plan (which includes the new point of interest) can besaved as a file in bulk memory circuit 316, and that entire file couldbe transferred to the architect computer 50.

It will be understood that the architect computer 50 could comprise a“fixed” unit that essentially remains in the architect's office, andpasses data to the remote unit 300 while the remote unit is physicallyat the office, or perhaps they remotely communicate with one another viaa wide area network, such as the Internet. Alternatively, the architectcomputer 50 could comprise a “portable” unit that is transported to thejobsite, and communicates with portable unit 300 while on site. Finally,as portable computers become even smaller in physical size, it is morelikely that the portable unit and the architect computer will eventuallybecome merged into a single device.

A display driver circuit 340 is in communication with the I/O circuit318. Display driver circuit 340 provides the correct interface and datasignals for a display 342 that is part of remote unit 300. If remoteunit 300 is a laptop computer, for example, then this would be thestandard display seen in most laptop computers. Or, perhaps the remoteunit 300 is a calculator-sized computing device, such as a PDA (PersonalDigital Assistant), in which case the display would be a much smallerphysical device. Display 342 could be a touch screen display, ifdesired.

One example of a type of remote unit that could work in this system(with some modification) is the portable “layout manager,” which is anexisting hand held computer sold by Trimble Navigation Limited, ModelNumber LM80. It should be noted that one cannot simply take the LM80 andimmediately use it as a remote unit in the present system; the softwaremust be modified to perform the necessary calculations, which aredescribed below. In addition, the input/output circuits must be modifiedto be able to communicate commands and data both to and from the baseunits.

A keypad driver circuit 350 is in communication with I/O circuit 318.Keypad driver circuit 350 controls the signals that interface to aninput sensing device 352, such as a keypad, as depicted on FIG. 4.Again, if the display 342 is of a touch screen type, then there may notbe a separate keypad on remote unit 300, because most of the command ordata input functions will be available by touching the display itself.There may be some type of power on/off switch, but that would notnecessarily be considered a true keypad (and typically would not be usedfor entering data).

Details of System Methodology

Referring now to FIG. 5, a flow chart is provided for a routine thatperforms a system set-up function. Beginning with an initialization step400, the user positions two base units, and then places both base unitsinto their set-up mode of operation, at a step 402 on FIG. 5. Beginningat a step 410, the two base units are aligned using a predeterminedroutine. An example of how this alignment occurs is provided below, andalso is illustrated beginning at FIG. 14.

At a step 412, the alignment routine begins by aiming the laser beam ofbase unit “A” at a target that is located on base unit “B.” A similarsituation occurs at the opposite laser transmitter; at a step 414 thelaser beam of base unit “B” is aimed at a target on the base unit “A.”(See a more detailed description below, in connection with FIGS. 14-19.)

At a step 416, the angular aim of both base units is adjusted untiltheir laser beams create an alignment axis. If a manual or visualalignment is going to be used, then the logic flow travels to a step418. Alternatively, an automatic alignment occurs if there are laserreceivers mounted to the base units; in that situation the logic flow isdirected to a step 420.

Once an alignment axis is created, a step 422 allows the operator toenter data from the angular encoders to the remote unit. The user wouldtypically be handling the remote unit itself (i.e., remote unit 420),and by entering a command on its keypad or touch screen, the remote unit40 will request the alignment information from both base units, and thenstore that angular encoder information into the memory circuit 316 ofremote unit 300. Once this has occurred, the two laser transmitters ofbase units “A” and “B” are situated in a fixed relationship with respectto one another, and are ready for a floor layout session. The logic flownow arrives at a step 430, which begins a routine that establishes thebenchmarks.

To establish benchmarks, a step 432 requires the user to visually locatetwo benchmark points on the floor surface at the jobsite. At a step 434,the user selects a first benchmark point, designated “B1.” The user nowaims both laser beams for base unit A and base unit B at this point B1.This will be very easy to do, because the laser beams are actuallyvertical laser planes, and if the light emanating from the lasertransmitters comprises visible light, then there will be a thin line ofvisible light crossing the floor surface from each of the base units Aand B. After both laser beams are aimed directly at the first benchmarkpoint B1, then there will be an intersection of the two laser beamsexactly at benchmark point B1. Once that occurs, the user can enter theaiming data for point B1 into the remote unit at a step 436. Thisestablishes the angular relationship between the two base units A and Band the first benchmark point B1.

The user now selects a second benchmark point “B2,” at a step 440. Bothlaser beams from both base units are now aimed at point B2, in a similarfashion to that described above for benchmark point B1, at step 434.After both laser beams are correctly pointed, there will be a visibleline intersection exactly at benchmark point B2, and the user willeasily see this if the laser beams are emanating visible light. Oncethat has occurred, the user can enter the point B2 aiming data into theremote unit, at a step 442.

Once the remote unit has both sets of aiming data for both benchmarkpoints B1 and B2, then a step 450 allows the remote unit to calculatethe coordinates of benchmark points B1 and B2 on the virtual floor planthat is contained in the memory circuit 316 of the remote unit 300,using these base unit positions. These calculations can use a set ofexample equations that are provided hereinbelow:

The following are general case calculations for setting up the system.It is expected that the two transmitters will be placed in someconvenient locations for the job site. The axis between the twotransmitters will be established by aligning the fan beams relative toeach other. It will be desired to calculate the distance between the twotransmitters. See, FIG. 22 for a diagram that illustrates therelationship of physical points and angles involved in the set-uproutine.

Definitions:

-   -   T1 Transmitter 1    -   T2 Transmitter 2    -   B1 Benchmark 1 (Known point—previously established)    -   B2 Benchmark 2 (Known point—previously established)    -   A1 Axis between the two transmitters

Knowns:

-   -   D Distance between Benchmark 1 and Benchmark 2    -   A1 The axis between the two transmitters.    -   α Angle transmitter 1 measures from the axis A1 to Benchmark 2    -   γ Angle transmitter 2 measures from the axis A1 to Benchmark 1    -   β Angle Transmitter 1 measures between Benchmark 1 and Benchmark        2    -   δ Angle Transmitter 2 measures between Benchmark 1 and Benchmark        2

It is desired to find the distance ‘d’ between the transmitters T1 andT2:

$\begin{matrix}{{\frac{d}{\sin \left( {\pi - \alpha - \beta - \gamma} \right)} = \frac{a}{\sin (\gamma)}}{{\tan (\gamma)} = \frac{a \cdot {\sin \left( {\alpha + \beta} \right)}}{r}}} & {{Eq}.\mspace{14mu} 1} \\{r = \frac{a \cdot {\sin \left( {\alpha + \beta} \right)}}{\tan (\gamma)}} & {{Eq}.\mspace{14mu} 3} \\{{\frac{d}{\sin \left( {\pi - \alpha - \gamma - \delta} \right)} = \frac{b}{\sin (\alpha)}}{{\tan (\alpha)} = \frac{b \cdot {\sin \left( {\gamma + \delta} \right)}}{s}}} & {{Eq}.\mspace{14mu} 2} \\{s = \frac{b \cdot {\sin \left( {\gamma + \delta} \right)}}{\tan (\alpha)}} & {{Eq}.\mspace{14mu} 4} \\{{\sin (\rho)} = \frac{{b \cdot {\sin \left( {\gamma + \delta} \right)}} - {a \cdot {\sin \left( {\alpha + \beta} \right)}}}{D}} & {{Eq}.\mspace{14mu} 5} \\{{{r + s - d} = {D \cdot {\cos (\rho)}}}{{From}\mspace{14mu} {{Eq}.\mspace{14mu} 1}\text{:}}{a = \frac{d \cdot {\sin (\gamma)}}{\sin \left( {\pi - \alpha - \beta - \delta} \right)}}{{Substitute}\mspace{14mu} {{Eq}.\mspace{14mu} 1}\mspace{14mu} {into}\mspace{14mu} {{Eq}.\mspace{14mu} 3}\text{:}}} & {{Eq}.\mspace{14mu} 6} \\{{r = \frac{d \cdot {\sin (\gamma)} \cdot {\sin \left( {\alpha + \beta} \right)}}{{\sin \left( {\pi - \alpha - \beta - \gamma} \right)} \cdot {\tan (\gamma)}}}{{From}\mspace{14mu} {{Eq}.\mspace{14mu} 2}\text{:}}{b = \frac{d \cdot {\sin (\alpha)}}{\sin \left( {\pi - \alpha - \gamma - \delta} \right)}}{{Substitute}\mspace{14mu} {{Eq}.\mspace{14mu} 2}\mspace{14mu} {into}\mspace{14mu} {{Eq}.\mspace{14mu} 4}\text{:}}} & {{Eq}.\mspace{14mu} 7} \\{{s = \frac{d \cdot {\sin (\alpha)} \cdot {\sin \left( {\gamma + \delta} \right)}}{{\sin \left( {\pi - \alpha - \gamma - \delta} \right)} \cdot {\tan (\alpha)}}}{{Substitute}\mspace{14mu} {{Eq}.\mspace{14mu} 1}\mspace{14mu} {and}\mspace{14mu} {{Eq}.\mspace{14mu} 2}\mspace{14mu} {into}\mspace{14mu} {{Eq}.\mspace{14mu} 5}\text{:}}} & {{Eq}.\mspace{14mu} 8} \\{{\rho = {\sin^{- 1}\left\lbrack {\frac{d \cdot {\sin (\alpha)} \cdot {\sin \left( {\gamma + \delta} \right)}}{D \cdot {\sin \left( {\pi - \alpha - \gamma - \delta} \right)}} - \frac{d \cdot {\sin (\gamma)} \cdot {\sin \left( {\alpha + \beta} \right)}}{D \cdot {\sin \left( {\pi - \alpha - \beta - \gamma} \right)}}} \right\rbrack}}{{Substitute}\mspace{14mu} {{Eq}.\mspace{14mu} 7}\mspace{14mu} {and}\mspace{14mu} {{Eq}.\mspace{14mu} 8}\mspace{14mu} {into}\mspace{14mu} {{Eq}.\mspace{14mu} 6}\text{:}}} & {{Eq}.\mspace{14mu} 9} \\{{d = \frac{D \cdot {\cos (\rho)}}{\begin{matrix}{\frac{{\sin (\gamma)} \cdot {\sin \left( {\alpha + \beta} \right)}}{{\sin \left( {\pi - \alpha - \beta - \gamma} \right)} \cdot {\tan (\gamma)}} +} \\{\frac{{\sin (\alpha)} \cdot {\sin \left( {\gamma + \delta} \right)}}{{\sin \left( {\pi - \alpha - \gamma - \delta} \right)} \cdot {\tan (\alpha)}} - 1}\end{matrix}}}{{{Eq}.\mspace{14mu} 10}a\mspace{14mu} {can}\mspace{14mu} {also}\mspace{14mu} {be}\mspace{14mu} {written}\text{:}}} & {{{Eq}.\mspace{14mu} 10}a} \\{d = \frac{\begin{matrix}{D \cdot {\cos (\rho)} \cdot {\sin \left( {\pi - \alpha - \beta - \gamma} \right)} \cdot} \\{{\sin \left( {\pi - \alpha - \gamma - \delta} \right)} \cdot {\tan (\gamma)} \cdot {\tan (\alpha)}}\end{matrix}}{\begin{matrix}{{{\sin (\gamma)} \cdot {\sin \left( {\alpha + \beta} \right)} \cdot {\sin \left( {\pi - \alpha - \gamma - \delta} \right)} \cdot {\tan (\alpha)}} +} \\{{\sin (\alpha)} \cdot {\sin \left( {\gamma + \delta} \right)} \cdot {\sin \left( {\pi - \alpha - \beta - \gamma} \right)} \cdot} \\{{\tan (\gamma)} - {{\sin \left( {\pi - \alpha - \beta - \gamma} \right)} \cdot}} \\{{\sin \left( {\pi - \alpha - \gamma - \delta} \right)} \cdot {\tan (\gamma)} \cdot {\tan (\alpha)}}\end{matrix}}} & {{{Eq}.\mspace{14mu} 10}b}\end{matrix}$

At this point is can be seen that two independent equations exist here:Eq. 9 and Eq. 10. These can be solved simultaneously through variousnumerical method techniques.

Once the calculations have been completed and both benchmarks have beenentered into remote unit 300, the logic flow arrives at a step 452, inwhich the system set-up routine is now completed. The positions of bothbase units A and B have been “registered” or “mapped” into the virtualfloor plan, which is stored either in the bulk memory circuit 316 of theremote unit 300 (which could be a removable flash memory chip), or isstored in the architect computer 50, which is in communication with theremote unit 300 via its communication port Y (at 320). The system is nowready to locate other points on the floor plan.

It should be noted that, if the two base units 20 and 30 had beenpreviously positioned at the same locations where they currently rest,then in theory, the set-up procedure of the flow chart of FIG. 5 wouldnot be necessary now. However, the user may desire to verify those baseunit positions, to be certain that one of the base units had not beenmoved without knowledge of the user. Their positions can be easilyverified by commanding the two base units to “aim” at the benchmarkpoints, one benchmark at a time. If the base units had not be moved,then the laser light lines projected by laser transmitters 22 and 32will form intersecting lines exactly at the correct physical locationson the jobsite floor surface, and this quickly verifies the set-upparameters.

Referring now to FIG. 6, a flow chart is provided for a routine to finda “known” point on the virtual floor plan. The routine begins at a step500, in which two base units and two known benchmarks have beenestablished on the virtual floor plan of the remote unit 300. The logicflow now is directed to a step 510, in which the user enters coordinatesfor a point of interest. This entry is done via either an input sensingdevice 352 (e.g., a keypad), or via a touch screen display (such asdisplay 342) of the remote unit 300. These coordinates can be enteredusing the virtual floor plan that was on the architect's computer 50,and those coordinates will be automatically translated to a set ofaiming data for the base units that contain the laser transmitters.

In essence, the coordinates for this known point of interest havealready been “predetermined” as far as the virtual floor plan isconcerned; the known point of interest has already been “registered” or“mapped” in the memory of the computer that holds the virtual floorplan. In previous (conventional) layout systems, the difficult part hasbeen to now identify, on the actual physical jobsite floor surface,exactly where that known point of interest is located, so that work maybe performed at the correct position.

The first laser beam of base unit “A” is slewed to aim the laser beam atthe entered coordinates, at a step 512. In a similar manner, a step 514causes the laser beam to be slewed for the base unit “B” to aim at thesame set of entered coordinates. After this has occurred, the two laserplanes from base units A and B will intersect on the floor surface atthe designated coordinates. The user, at a step 516, can now visuallylocate the intersecting point on the floor surface, and can commencework at that point.

The logic flow now arrives at a decision step 520, where it determinesif there will be work at the ceiling level. If not, the logic flow isdirected to a step 530. If the answer is YES, then the user willvisually locate the intersecting point of the two laser planes on theceiling surface at a step 522. The user will now be able to commencework at that point. This would be useful for installing sprinklers,smoke detectors, or lighting fixtures, for example, as per thearchitect's plan.

The logic flow now arrives at a decision step 530, where it determineswhether or not there will be work along a vertical wall. If not, thenthe logic flow is directed to a step 534. If the answer is YES, then theuser will visually locate the intersecting line on the wall surface at astep 532. This is the implied plumb line that exists between the floorand ceiling intersecting points of the two laser planes. Now that a wallsurface has the vertical plumb line visible along the wall's surface,the user can commence work along that line. This can be useful forplacing electrical outlets, or for framing, or even for positioning thewall in the first place.

The logic flow now arrives at a step 534, and the routine is nowcompleted for this location. A decision step 540 now determines whetheror not the user is ready for another point of interest. If not, thelogic flow is directed to a step 542, where this routine is completed.If the user is ready for another point of interest, then the logic flowis directed back to step 510, which allows the user to enter coordinatesfor a new point of interest on the remote unit 300.

An example set of position calculations is provided below. Thiscalculation set describes a method to solve for the aiming angles whenlaying out the location of a known point of interest once the system isset up; it solves for the angles each transmitter must drive to in orderto present a point of interest that is desired to be found. See, FIG. 23for a diagram that illustrates the relationship of physical points andangles involved in the routine for locating a known point of interest.

Definitions:

-   -   T1 Transmitter 1    -   T2 Transmitter 2    -   B1 Benchmark 1 (Known point—previously established)    -   B2 Benchmark 2 (Known point—previously established)    -   A1 Axis between the two transmitters

Knowns:

-   -   d Distance between transmitters    -   A:(X_(A), Y_(A)) Coordinates of the Point of Interest to be        Found

Process:

-   -   1) Enter the coordinates of the Point of interest into the        system remote.    -   2) Transmitters 1 and 2 drive to the corresponding angles θ and        φ needed to present point A:(X_(A), Y_(A)).    -   3) Visually locate where the planes intersect.

From the Diagram:

a=X_(A) and b=Y_(A)

Solving for θ and φ:

$\theta = {\tan^{- 1}\left( \frac{b}{a} \right)}$$\varphi = {\tan^{- 1}\left( \frac{b}{d - a} \right)}$

Referring now to FIG. 7, a routine to enter an “unknown” point isprovided as a flow chart. The routine begins at a step 600, in which twobase units and two known benchmarks have already been established on thevirtual floor plan at this step. A step 610 now locates a “new” physicalpoint of interest on a surface that is within the working floor plan.This new point of interest is not already plotted on the virtual floorplan—if it was, it would not be “unknown.” Instead, this new point issomething that the user has decided should be now plotted on the virtualfloor plan, and it is a physical point that the user can actually see,and that he/she wants to now have memorialized within the floor plancomputer files.

After the new point of interest has been physically located at step 610,a step 612 requires the user to aim the laser beam of base unit “A” atthis point of interest. This means that the user must command (ormanually slew) the laser beam directly at the point of interest, so thatthe plane of laser light creates a line along the floor surface(assuming this point is on the floor surface) until that line visuallycrosses the point of interest.

After base unit “A” has been aimed at step 612, a step 614 now requiresthe user to aim the laser beam of base unit “B” at the same new point ofinterest. Again, the laser plane from base unit “B” will create a lineof laser light along the floor surface (again assuming this is a pointon the floor surface), and this creates a visible line that emanatesaway from base unit “B” and, after being properly aimed, the laser lightwill visually cross the new point of interest. At the end of this aimingphase in step 614, both laser planes should now intersect (as visiblelight lines on the floor surface) exactly at the point of interest.

The angular encoders will now have azimuth information that can bestored, and a step 620 enters data from the angular encoders of bothbase units into the remote unit. (This would typically occur via a usercommand entered on the remote unit.) Once the remote unit has this data,a step 622 causes the remote unit to execute a reverse calculation toplot the coordinates for this point of interest on the virtual floorplan. Once that has occurred, the unknown point of interest is now“registered” on the virtual floor plan, and that point of interestessentially becomes a “known” point of interest and thereby can be“found” later, even if the base units 20 and 30 are moved to otherlocations. A step 624 now is reached, at which the routine has beencompleted for this particular location (i.e., at this point ofinterest).

Alternatively, if the base units do not have azimuth encoders, then theywill be equipped with a visual angle scale that the user can see on anupper surface of the base units. After the user has (manually) aimed thelaser transmitter for each base unit (at steps 612 and 614), then he/shemay read the azimuth angular displacement for both laser transmitters,and that information can then be manually entered into the remote unitat step 620 (using its input sensing device 352). Once the remote unithas this data, steps 622 and 624 are performed, as described above.

A decision step 630 now determines whether or not the user is ready foranother “new” point of interest. If not, then the entire routine of FIG.7 has been completed at a step 632. On the other hand, if the user hasanother point of interest to be plotted at this time, then the logicflow is directed back to step 610, in which the user locates that otherphysical point of interest on a surface that is within the working floorplan.

By using the routine depicted in the steps of the flow chart on FIG. 7,a user can easily choose any point of interest on the jobsite that iswithin a non-interrupted view of both laser transmitters in both baseunits. Once the user has located that physical point, it is a simplematter to aim both laser transmitters directly at that point to createtwo intersecting lines of laser light from the laser planes emitted bythe two laser transmitters. This is very easy to do, because the usercan see everything that is going on, assuming the laser transmitters areemitting visible light. Even if the light is infrared, for example, theuser could be utilizing special night-vision goggles to locate thesepoints, if desired. This non-visible light scenario might be quiteuseful for applications that are to occur in the dark, and might evenhave military applications (for plotting positions of mines in aminefield, for example).

This routine of FIG. 7 can be performed much more quickly than a typicalsurveying function that is being performed countless times on jobsitesusing earlier technology. No type of surveyor's rod is necessary, andsuch a rod would not need to be positioned and plumbed for each newpoint of interest, such as is required in many of the systems usingavailable conventional technology.

If the user selects a point that is not within direct visible range ofone of the laser transmitters, it is a simple matter to move thatparticular laser transmitter to a different location within the virtualfloor plan and re-establish its set-up function using the routineillustrated as a flow chart in FIG. 5. Once the laser transmitter hasbeen placed at a new location, its position can easily be establishedwith benchmarks that are always available on a new jobsite, and onceeverything has been registered with the remote unit, the user candirectly begin to enter unknown points, using the flow chart of FIG. 7.

An example set of reverse calculations is provided below. Thiscalculation set describes a method to solve for the coordinates for thelocation of an unknown point of interest once the system is set up. See,FIG. 24 for a diagram that illustrates the relationship of physicalpoints and angles involved in the routine for entering an unknown pointof interest.

Definitions:

-   -   T1 Transmitter 1    -   T2 Transmitter 2    -   B1 Benchmark 1 (Known point—previously established)    -   B2 Benchmark 2 (Known point—previously established)    -   A1 Axis between the two transmitters

Knowns:

-   -   d Distance between transmitters    -   θ Angle measured by transmitter 1 from the axis between        transmitters and the point of interest    -   φ Angle measured by transmitter 2 from the axis between        transmitters and the point of interest

Process:

-   -   1) Command each transmitter to place each respective fan beam        over the point of interest.    -   2) Transmitters 1 and 2 measure the angles θ and φ.    -   3) Since d is known from the system setup, the coordinates of        point a can be calculated.

From the Diagram:

$y_{0} = \frac{d}{\frac{1}{\tan (\theta)} + \frac{1}{\tan (\varphi)}}$

This can be Written:

$y_{0} = \frac{d \cdot {\tan (\varphi)} \cdot {\tan (\theta)}}{{\tan (\theta)} + {\tan (\varphi)}}$

And:

$x_{0} = \frac{y_{0}}{\tan (\theta)}$

Further Operating Details

Referring now to FIG. 8, a diagrammatic view is provided for the main“mechanical” components found in a base unit, including a lasertransmitter and a laser receiver. The base unit is generally designatedby the reference numeral 100, and includes a leveling platform at thebottom of the structure, upon which is mounted a rotational unit foradjusting the azimuth angle of the laser transmitter. The levelingplatform includes two leveling motors 142, a level sensor 144 (e.g.,some type of electronic gravity sensor), and a pivot 146. Above theleveling motors 142, are leadscrews 148, and the horizontal levelingplatform is mounted on the top of the leadscrews 148.

It will be understood that a manual leveling platform could be providedwith base unit 100, rather than the “automatic” leveling platformdescribed in the previous paragraph. Such a manual leveling platformcould use a pendulum or a visible bubble, for example, and there wouldbe no automatic gravity sensing device or leveling motor drive.

On the upper surface of the leveling platform is the azimuth motor 162,which has output shaft and a pinion gear 164, which meshes with a spurgear 166. The spur gear has an output shaft that is vertical, which runsthrough an encoder disc subassembly 152 and up to a second wheel or discthat includes a pair of butt cell photosensors 220. The encoder discsubassembly 152 typically has some type of visible markings that can bedetected by an encoder readhead, which is located along the outerperimeter of the encoder disc. On FIG. 8, the encoder readhead isdesignated by reference numeral 154, and the overall angle encodersystem 150 includes both the encoder disc subassembly 152 and theencoder readhead 154. Typical optical encoders have a fixed portion anda rotatable portion, as depicted on FIG. 8 by the two parallel discstructures in subassembly 152.

A laser diode 172 is mounted (in this diagrammatic view) in thehorizontal direction, and it emits a laser light beam through acollimating lens 174, and that laser light travels through a cylinderlens 176 to create an output fan beam 178. The fan beam 178 isdiagrammatically presented on FIG. 8 as a diverging plane of laserlight.

In this arrangement, the azimuth motor 164 turns the aiming direction ofthe fan beam laser plane of light 178, and this simultaneously moves thebutt cell photosensors 220 and a portion of the encoder disc subassembly152. In a typical arrangement, the split between the butt cellphotosensors will be along the same vertical line as the edge view ofthe fan beam laser plane of light 178. However, it should be noted thatthe butt cell photosensors 220 could be somewhat offset from thecenterline of the plane of laser light 178, and the calculations fordetermining positions of various points in the floor layout system couldbe adjusted by those offset calculations, especially fordetermining/establishing an alignment axis. This optional arrangement,sometimes referred to as “characterizing” the photosensors, can make itsomewhat easier to construct the base unit, if desired.

A second photosensor is provided on FIG. 8. This is a “rod” sensor, andis depicted at reference numeral 230. In this rod sensor, however, thereis only a single photocell at 236. Although a typical position-sensingrod sensor would have two photocells (as depicted in FIG. 3), in theconfiguration of FIG. 8, the information being sought only requires asingle photocell. In the base unit 100, the information being sought iswhether or not laser light is impacting the rod sensor cylindricalsurface, and if so, a single photocell at 236 will detect that event. Onthe other hand, if greater sensitivity is desired, or if themanufacturer wishes to use a standard rod sensor that already has twophotocells mounted to the cylindrical rod (one on each end), then astandard rod sensor could be used, as depicted on FIG. 3.

As indicated on FIG. 8, the azimuth motor drive 162 can rotate theentire upper portion of the base unit in the horizontal plane; i.e., therotational axis is essentially vertical, once the leveling platform hasadjusted itself to making the system substantially horizontal withrespect to gravity.

An alternative arrangement could be used to build a lesser expensivebase unit 100. The photosensor 220 could be replaced by a smallreflector that is precisely positioned to be in vertical alignment withthe centerline of the plane of laser light 178. In this alternativeembodiment, the opposite laser transmitter would have to be manuallyaimed at the reflector, when determining an alignment axis. Thiscertainly would be more difficult to set up than the automated procedurethat is described below, but it is possible, particularly forshort-range situations in which the distance between the base units isrelatively small. The laser receivers 24 and 34 could be entirelyeliminated in this alternative embodiment.

Another way to reduce system cost is to eliminate the automatic azimuthaiming platform altogether, and instead rely on manual aiming of thelaser transmitters for both base units. This second alternativeembodiment would save the cost of the azimuth drive (including motor162) and the encoder system 150. Of course, the “aiming” azimuth anglesthen would have to be read manually from an arcuate scale on the baseunit, and these angles would have to be entered manually into the remoteunit by the user every time the laser transmitter is aimed at a newbenchmark point, a known point of interest, or an unknown point ofinterest. The possibility of errors in data entry would increase, evenif the azimuth angles are correctly read in the first place.

Referring now to FIGS. 9-13, a set of illustrations is provided to morereadily demonstrate the ease of use of the system being disclosedherein. In FIG. 9, a first step for aligning the axes of the two lasertransmitters is depicted. The laser transmitters are part of the baseunits 20 and 30, which are mounted on tripods in FIG. 9. A user,generally designated by the reference numeral 45, is depicted as holdinga hand-held remote unit 40, within the confines of an enclosed space (orroom) 700. The room 700 has a ceiling surface 710 and floor surface 712.

The laser transmitter at base unit 20 emits a laser fan beam, which hasan upper angular limit line at 722 and a lower angular limit line at724. The other laser transmitter at base unit 30 also emits a fan beamof laser light, and has an upper angular limit line at 732 and a lowerangular limit line at 734. The object in this step of FIG. 9 is to alignan axis 740 between the two laser transmitters. The methodology for adetailed alignment procedure is described below, in reference to FIGS.14-19. At this point in the description, it will be assumed that thealignment axis 740 is being determined by this procedure.

FIG. 10 illustrates the next step, which aligns the two lasertransmitters to a first benchmark point (referred to on FIG. 10 as“Benchmark 1”). In FIG. 10, the interior space (or room) is referred toas reference numeral 701. The two laser transmitters have been aimed atthe point of interest that is Benchmark 1, and is designated by thereference numeral 752. The two base units 20 and 30 have either hadtheir lasers manually aimed by the user, or automatically adjusted bythe user using the remote unit 40, if azimuth positioning motors andencoders are available on base units 20 and 30. After the two laserplanes have been aimed so that they will intersect the first benchmarkat 752, the laser planes will have an appearance as illustrated on FIG.10. The laser plane from the fan beam laser transmitter of base unit 20will again have angular limit lines 722 and 724, but will also produce avisible line along the ceiling at 726, and a similar visible line alongthe floor surface at 728. In a similar manner, the laser transmitterproducing the fan beam from base unit 30 will emit angular limit lines732 and 734, and also produces an upper visible line along the ceilingat 736 and a lower visible line along the floor surface at 738.

It will be understood that, as used herein, the terms “visible light” or“visible laser light” refer to laser light beams that are eitherdirectly visible by the human eye (i.e., having a wavelength in therange of approximately 430 nm to 690 nm), or refer to laser beams thatare somewhat outside of the above “normal” range of visible acuity forhuman eyes, and the user is being aided by some type of special lenses.For example, the laser transmitters described herein could produceinfrared (IR) laser light beams if desired, and the user could bewearing night-vision goggles; in that situation, the laser light beamswould appear to be “visible” to that user, which is more or lessnecessary to properly use the alignment and location features of thesystem described herein.

The two lower laser plane edges 728 and 738 will intersect exactly atthe benchmark point 752, after the two laser transmitters have beencorrectly adjusted for their angular position along the azimuthdirection, and the user will be able to visibly see that intersectionpoint. Moreover, the two laser planes will intersect along a verticalline 750, which will be a plumb line if the two base units have beencorrectly leveled. This laser line of intersection 750 will actually bevisible if a solid object, or some type of smoky substance, ispositioned along the line itself. At the top of the laser light line 750will be another visible intersection of “horizontal” lines along theceiling, which will be described below, in greater detail.

The third step is to align the laser transmitters for the two base unitsto the second benchmark point, which is referred to on FIG. 11 as“Benchmark 2.” The interior space (or room) is designated at thereference numeral 702 in FIG. 11. The user now is required to move theangular positions of both laser transmitters for the base units 20 and30 so that they are aimed at the second benchmark, which is designatedat reference numeral 762. Both laser transmitters continue to emit aplane of laser light, and the fan beam thereby produced has divergenceangles that are represented by the lines 722, 724, 732, and 734.Furthermore, there will be upper and lower visible lines along theceiling surface and floor surface, which again are designated by theline segments 726, 728, 736, and 738.

After the two laser transmitters have been properly aimed at the secondbenchmark 762, the lower visible lines of the two laser planes willintersect exactly at benchmark 762, and the user will be able to visiblysee that intersection point.

It will be understood that, as used herein, the phrase “intersectexactly” at a specific point on a surface means that the user hasadjusted the laser transmitters so that their emanating laser fan beamsproduce light lines that appear to be precisely crossing that specificpoint. Of course, there will likely be some small tolerance of error,and it is up to the user to make the proper adjustments in aiming thebase unit laser transmitters so that the light lines are as close to“exactly” crossing right at the proper location. Since the laser lightlines have a discernable width, the user cannot literally align thelaser beams within some imperceptible tiny distance, and thus, therewill likely be a very small tolerance of error in such “exact” positionsof the laser transmitter azimuth angles. However, this is a very smallerror indeed, and moreover, the user will quickly become very good atmaking these azimuth position changes of the laser transmitters suchthat any such errors will essentially be negligible.

As in the case of FIG. 10, there will also be an intersecting verticalline between the two laser planes, and this intersecting line isrepresented at the reference numeral 760 on FIG. 11. This intersectingline 760 is a plumb line, so long as the two laser transmitters havebeen properly leveled.

After both benchmark points have had their coordinates entered into theremote unit 40 (as per FIG. 10 and FIG. 11), the set-up of the systemhas been completed. Now the user will be able to enter other coordinatesof interest into the remote unit 40, and cause the laser transmitters toautomatically aim at those coordinates (assuming the laser transmittersare motorized and have angular encoders). FIG. 12 illustrates such asituation, in which the user has entered the coordinates of a floorpoint designated by the reference numeral 772 on FIG. 12. The enclosedspace (or room) is designated at the reference numeral 703 on FIG. 12.The laser transmitters have been aimed so that their fan beams eachproduce a plane of laser light that is vertical, and both of theseplanes of laser light intersect exactly at the point 772 along the floorsurface 712. There will also exist a vertical line of intersectionbetween the two laser planes at the reference numeral 770. This will bea plumb line, as described before, so long as the laser base units 20and 30 have been correctly leveled. More importantly, the two lasertransmitters need to output laser planes that are substantially verticalwith respect to gravity; if that correctly takes place, then the impliedline 770 will also be substantially vertical with respect to gravity.

Since the plumb line 770 exists as a vertical line directly above thefloor point 772, there will also be visible to the user a ceilingtransfer point that is designated by the reference numeral 774. The userwill see a pair of intersecting lines at point 774, which are producedby the two upper edges of the laser planes from the laser transmittersof base units 20 and 30. These are the upper edge lines of the fan laserbeams along the line segments 726 and 736, which follow along thesurface of the ceiling 710. This provides the user with a virtuallyinstantaneous transfer point along the ceiling surface, every time theuser first designates a floor point of interest. The ceiling transferpoint 774 is automatically plumb above the floor point 772, since theimplied line 770 is truly plumb. This system allows the buildingdesigner to lay out devices that are to be installed in the ceiling byusing the coordinates on a two-dimensional floor plan, if desired.

The technology disclosed herein automatically can take floor points andtransfer those coordinates to the ceiling; furthermore if the buildingplan was a three-dimensional plan, then a ceiling set of coordinatescould first be entered instead of a floor set of coordinates. In thatmode of operation, the two laser transmitters of base units 20 and 30will still be able to slew automatically so that their laser fan beamswill intersect the ceiling set of coordinates instead of the floor setof coordinates. The final appearance will be the same, just like what isillustrated in FIG. 12. The only difference will be that the ceilingpoint was determined first, instead of the floor point. There will stillexist a plumb line 770 after the ceiling point has been laid out.

Referring now to FIG. 13, the ability of the system disclosed herein tocreate a vertical plumb line of laser light will be used advantageously.An enclosed space (or room) 704 is depicted on FIG. 13, and the twolaser transmitters of base units 20 and 30 have been aimed at a floorpoint 782 that is located just along the edge of one of the walls, whichis designated by the reference numeral 714. The laser fan beams willcreate a visible plumb line of laser light 780 that will be visiblealong the surface of the wall 714. There also will exist a ceilingintersecting point at 784, that is the top point of the line segment 780that makes up this intersecting line between the two planes of laserlight. For the implied laser plumb line 780 to be visible along the wallsurface, the wall must be positioned at or fairly close to theintersecting point 782; this can be termed a “proximal” relationship—thewall must have its surface 714 proximal to the point 782, or theintersecting line of laser light 780 will “miss” the wall surface, andnot be visible on that wall surface. Of course, the wall itself must befairly plumb, or the plumb line 780 will not properly appear along thewall's surface.

As discussed in the previous paragraph, if a two-dimensional floor planis available, then the user can start with the floor intersecting point782 as the point of interest. On the other hand, if a three-dimensionalset of floor plans is available, and if the ceiling intersecting point784 has coordinates that are available to the user, then that pointcould be used to cause the laser transmitters to be aimed as depicted inFIG. 13.

After the plumb line 780 appears along the wall surface 714, the usercan use that plumb line to help align and set studded wall. In addition,once the walls have been installed, the vertical plumb line 780 can beused to help locate the positions for installation of wall outlets orHVAC ducts or vents, and other similar devices that are placed in wallsof buildings.

Referring now to FIGS. 14-19, an example of a methodology forestablishing an alignment axis between two base units is provided.Referring now to FIG. 14, the two base units 20 and 30 are emittingvertical planes of laser light in a fan beam shape, in which the planeof laser light for base unit 20 is designated by the reference numeral60, and the plane of laser light from base unit 30 is designated by thereference numeral 70. As can be seen in FIG. 14, laser light planes 60and 70 intersect one another, but they are not aligned, nor do theyintersect the opposite base unit.

In FIG. 14, base unit 20 has a positioning photosensor at 64, whichtypically can be a “butt cell” set of photocells that are preciselyaligned to the center of the emitted laser fan beam. Base unit 20 has asecond photosensor at 62 that comprises a photocell and a cylinder lens.The cylinder lens extends vertically above the top of the base unitstructure (this is similar to element 230 on FIG. 8), and the photocellis attached at one end of the cylinder lens (which is similar to thephotocell 236 on FIG. 8). This photocell and cylinder lens combination62 is roughly aligned to the rotation center of base unit 20. (It doesnot need to be precisely aligned. Photosensor 62 provides “gross”alignment sensing capability for detecting the laser beams of the otherlaser transmitter, from base unit 30.)

In a similar fashion, base unit 30 also includes a positioningphotosensor 74 which typically can be a “butt cell” array of photocells,which are precisely aligned to the center of the emitted laser fan beam70. (Note: this “precise” alignment could include characterizing thearray of photocells to correct for any offset, in case the position ofthe laser beam output and the photosensor's null point are not perfectlyaligned.) Also, base unit 30 includes a cylinder lens and photocellcombination at 72, which is roughly (not precisely) aligned to therotation center of that base unit. Photosensor 72 provides “gross”alignment sensing capability for detecting the laser beams of the otherlaser transmitter, from base unit 20.

Referring now to FIG. 15, the user has entered a command so that eachbase unit will begin to rotate. The purpose of this rotation is to havethe cylinder lens/photocell combination (either 62 or 72) detect thelaser beam from the other base unit. In FIG. 15, it can be seen thatboth laser fan beams have changed position, but neither fan beam 60 or70 are intersecting the other base unit. Laser fan beam 60 is rotatingin the direction of an angular arc line 66, while base unit 30 has itslaser transmitter beam 70 rotating in the direction of an angular line76.

Referring now to FIG. 16, the laser fan beam 70 has intersected thevertical photosensor 62 of base unit 20. When this occurs, base unit 30can stop rotating its fan beam 70, because it is now roughly in thecorrect position. However, the fan beam 60 from base unit 20 still needsto continue rotating in the direction 66. In FIG. 17, the fan beam 60 isstill rotating from base unit 20, but has not yet intersected base unit30. The fan beam 70 from base unit 30 has stopped, and is stillintersecting the vertical photosensor 62.

Referring now to FIG. 18, the laser fan beam 60 from base unit 20 hasintersected the photosensor 72 of base unit 30, and the lasertransmitter at base unit 20 now will stop rotating. At this time, bothfan beams 60 and 70 are roughly aligned with the opposite base units 30and 20 respectively.

Referring now to FIG. 19, the positioning photocells 64 and 74 now comeinto play. Assuming these two photocells each comprise a pair of buttcell photosensors, they will have a deadband width between the twophotosensitivity areas of the butt cell arrangement, and this deadbandwidth is the desired position that will be sought by the two laser fanbeams 60 and 70. Using the positioning photocells 64 and 74, the laserreceivers on the two base units 20 and 30 will be able to determine theexact position of the laser strike of the fan beams 60 and 70 within avery small tolerance. The output signals from the laser receivers can beused to command the azimuth positioning motors of both lasertransmitters for the base units 20 and 30 to move in small amounts untilthe vertical edge of the laser planes 60 and 70 are striking the buttcell deadband positions.

The butt cell deadband width can be made quite small, perhaps as smallas 0.005 inches, if desired. In FIG. 19, the two laser transmitters arerotated iteratively until each of their fan beams are striking withinthe deadband width of the butt cells on the opposite base unit. Thiswill now provide a very precise alignment axis between the two baseunits 20 and 30.

Another benefit of the technology disclosed herein is illustrated onFIGS. 20 and 21. FIG. 20 illustrates a conventional (prior art) laserpointing system that is currently used for floor layout procedures. Thisprior art system is generally designated by the reference numeral 800,and it includes a laser transmitter 810 that is mounted on a tripod, andthis assembly is placed on a floor surface 812. This pointing lasersystem is designed to literally point its laser beam 820 directly at aparticular spot on the floor surface 812, and that spot visuallydesignates the point of interest for the user. This system will work, solong as the floor surface is actually flat and horizontal within thetolerance required for the laser pointer system to successfullydesignate the point of interest.

However, if there is any kind of unevenness in the floor, such as adepression that is designated by the reference numeral 814, then theaccuracy of laser pointing system 800 is completely thrown off. It willbe understood that the depression 814 could just as easily be aprotrusion in the floor surface, and that would also negatively impactthe accuracy of the system 800.

The reference numeral 822 designates the true position for the point ofinterest on the floor surface where laser beam 820 is attempting todesignate that position. However, because of the depression in the floorat 814, the projected point on this uneven surface is at a differentphysical location in the horizontal direction, which is designated bythe reference numeral 824. This causes a position error that isdesignated by the reference numeral 830. Depending upon the horizontaldistance between the true position 822 and the position of the lasertransmitter 810, the position error 830 can be significant, and willrender the system useless for its intended accuracy.

Referring now to FIG. 21, the technology disclosed herein can be usedwith two laser transmitters, as described above, and this type of systemis generally designated by the reference numeral 900. A first lasertransmitter is at 910, and a second laser transmitter is at 911. Lasertransmitters 910 and 911 are both mounted on tripods, and both emit alaser fan beam (in this example), in which the fan beam for lasertransmitter 910 is designated by the reference numeral 920, and the fanbeam for laser transmitter 911 is designated by the reference numeral921.

Both laser transmitters are positioned on a floor surface, which isgenerally designated by the reference numeral 912. A point of interestis entered into the system that controls the azimuth of both lasertransmitters 910 and 911, and therefore, they will be aimed at thecorrect location on the floor surface. On FIG. 21, the true position ofthe point of interest is designated by the reference numeral 922. It sohappens that the point of interest 922 lies in a depression in thefloor, which is designated by the reference numeral 914. However, thevertical planes of the two laser fan beams 920 and 921 intersect in avertical plumb line at 950, and this plumb line will run from itsuppermost limit at the top edge of the laser fan beams 920 and 921 downto its lowermost limit (along line 950), which intersects the floorsurface in the depression 914, at a point 924.

Because of the way system 900 operates to create the plumb line 950, theindicated position of the point of interest at 924 will fall exactly atthe true position of the point of interest at 922. Therefore, no errorwill occur between the true position 922 and the point that is projectedonto the floor surface 924, even when that projected point falls withina depression, such as the depression 914. This will also be true if,instead of a depression, there is a protrusion in the floor surface.This feature is a very significant advantage provided by the technologydisclosed herein.

It will be understood that some of the logical operations described inrelation to the flow charts of FIGS. 5-7 can be implemented inelectronic equipment using sequential logic (such as by usingmicroprocessor technology), or using a logic state machine, or perhapsby discrete logic; it even could be implemented using parallelprocessors. One preferred embodiment may use a microprocessor ormicrocontroller (e.g., one of the microprocessor 110, 210, or 310) toexecute software instructions that are stored in memory cells within anASIC. In fact, the one entire microprocessor (or a microcontroller, forthat matter), along with RAM and executable ROM, may be contained withina single ASIC, in one mode of the technology disclosed herein. Ofcourse, other types of circuitry could be used to implement theselogical operations depicted in the drawings without departing from theprinciples of the technology disclosed herein. In any event, some typeof processing circuit will be provided, whether it is based on amicroprocessor, a logic state machine, by using discrete logic elementsto accomplish these tasks, or perhaps by a type of computation devicenot yet invented; moreover, some type of memory circuit will beprovided, whether it is based on typical RAM chips, EEROM chips(including Flash memory), by using discrete logic elements to store dataand other operating information (such as the point coordinates datastored, for example, in memory elements 312 or 316), or perhaps by atype of memory device not yet invented.

It will also be understood that the precise logical operations depictedin the flow charts of FIGS. 5-7, and discussed above, could be somewhatmodified to perform similar, although not exact, functions withoutdeparting from the principles of the technology disclosed herein. Theexact nature of some of the decision steps and other commands in theseflow charts are directed toward specific future models of lasertransmitter and receiver systems, and floor layout portable computers(those involving Trimble Navigation laser and floor layout equipment,for example) and certainly similar, but somewhat different, steps wouldbe taken for use with other models or brands of laser equipment andfloor layout computer systems in many instances, with the overallinventive results being the same.

As used herein, the term “proximal” can have a meaning of closelypositioning one physical object with a second physical object, such thatthe two objects are perhaps adjacent to one another, although it is notnecessarily required that there be no third object positionedtherebetween. In the technology disclosed herein, there may be instancesin which a “male locating structure” is to be positioned “proximal” to a“female locating structure.” In general, this could mean that the twomale and female structures are to be physically abutting one another, orthis could mean that they are “mated” to one another by way of aparticular size and shape that essentially keeps one structure orientedin a predetermined direction and at an X-Y (e.g., horizontal andvertical) position with respect to one another, regardless as to whetherthe two male and female structures actually touch one another along acontinuous surface. Or, two structures of any size and shape (whethermale, female, or otherwise in shape) may be located somewhat near oneanother, regardless if they physically abut one another or not; or avertical wall structure could be positioned at or near a specific pointon a horizontal floor or ceiling surface; such a relationship could betermed “proximal.” Moreover, the term “proximal” can also have a meaningthat relates strictly to a single object, in which the single object mayhave two ends, and the “distal end” is the end that is positionedsomewhat farther away from a subject point (or area) of reference, andthe “proximal end” is the other end, which would be positioned somewhatcloser to that same subject point (or area) of reference.

All documents cited in the Background and in the Detailed Descriptionare, in relevant part, incorporated herein by reference; the citation ofany document is not to be construed as an admission that it is prior artwith respect to the technology disclosed herein.

The foregoing description of a preferred embodiment has been presentedfor purposes of illustration and description. It is not intended to beexhaustive or to limit the technology disclosed herein to the preciseform disclosed, and the technology disclosed herein may be furthermodified within the spirit and scope of this disclosure. Any examplesdescribed or illustrated herein are intended as non-limiting examples,and many modifications or variations of the examples, or of thepreferred embodiment(s), are possible in light of the above teachings,without departing from the spirit and scope of the technology disclosedherein. The embodiment(s) was chosen and described in order toillustrate the principles of the technology disclosed herein and itspractical application to thereby enable one of ordinary skill in the artto utilize the technology disclosed herein in various embodiments andwith various modifications as are suited to particular usescontemplated. This application is therefore intended to cover anyvariations, uses, or adaptations of the technology disclosed hereinusing its general principles. Further, this application is intended tocover such departures from the present disclosure as come within knownor customary practice in the art to which this technology disclosedherein pertains and which fall within the limits of the appended claims.

What is claimed is:
 1. A layout and point transfer system, comprising:(a) a first base unit, having a first laser light transmitter that emitsa first laser light plane, and a first processing circuit; and (b) asecond base unit, having a second laser light transmitter that emits asecond laser light plane, and a second processing circuit; wherein: (c)said system is configured to register locations of said first and secondbase units on a physical jobsite surface with respect to at least twobenchmark points that are also located on said physical jobsite surface;and (d) said system is configured to provide a visual representation ofa virtual point on said physical jobsite surface, by aiming first laserlight plane in a first static direction and said second laser lightplane in a second static direction, to indicate a location of saidvirtual point.
 2. The system of claim 1, wherein: (a) said first laserlight plane creates a first visual laser light line along said physicaljobsite surface; (b) said second laser light plane creates a secondvisual laser light line along said physical jobsite surface; and (c)said visual representation comprises said first and second visual laserlight lines intersecting at said virtual point.
 3. The system of claim1, wherein: said first plane of laser light, and said second plane oflaser light comprise at least one of: (a) electromagnetic energy of awavelength that is directly visible to a human eye; and (b)electromagnetic energy of a wavelength that is not directly visible to ahuman eye, but which is perceptible to a human user by an additionallight-sensitive viewing device used by said human user.
 4. The system ofclaim 1, wherein said first and second planes of laser light comprise atleast one of: (a) a static laser fan beam; and (b) a rotating laserlight beam.
 5. The system of claim 4, wherein a user is able to visiblysee an intersection of said first static visual laser light line andsecond static visual laser light line at said virtual point.
 6. Thesystem of claim 1, wherein: (a) said first laser light plane intersectssaid second laser light plane at a implied line that is substantiallyvertical with respect to gravity if said first and second lasertransmitters are providing substantially vertical said first and secondlaser light planes with respect to gravity; and (b) said substantiallyvertical implied line intersects said physical jobsite surface at saidvirtual point.
 7. The system of claim 6, wherein: said substantiallyvertical implied line also intersects a second physical jobsite surfaceat a different elevation, and thereby provides a second visualrepresentation of a second virtual point that is plumb with respect tosaid virtual point.
 8. The system of claim 7, wherein: (a) said firstlaser light plane creates a third visual laser light line along saidsecond physical jobsite surface; (b) said second laser light planecreates a fourth visual laser light line along second said physicaljobsite surface; and (c) said second visual representation comprisessaid third and fourth visual laser light lines intersecting at saidsecond virtual point.
 9. The system of claim 6, wherein: saidsubstantially vertical implied line runs along a substantially verticalsurface, and substantially vertical implied line thereby becomes avisible plumb line along said substantially vertical surface.
 10. Thesystem of claim 1, further comprising: a remote unit, having a thirdprocessing circuit, wherein: (a) said remote unit contains a virtualfloor plan for use at said physical jobsite surface; and (b) saidvirtual floor plan includes coordinates for said at least two benchmarkpoints.
 11. The system of claim 10, wherein: (a) said first base unitfurther comprises: (i) a first self-leveling device; (ii) a firstazimuth position encoder; (iii) a first azimuth motor drive forautomatic positioning said first laser light transmitter, under controlof said remote unit; and (b) said second base unit further comprises:(i) a second self-leveling device; (ii) a second azimuth positionencoder; (iii) a second azimuth motor drive for automatic positioningsaid second laser light transmitter, under control of said remote unit.12. The system of claim 11, wherein: (a) said virtual point waspreviously registered on said virtual floor plan, relative to said atleast two benchmark points, and said virtual point is selected as aknown point of interest with predetermined coordinates on said virtualfloor plan, and, by use of a first command entered on said remote unitby a user, said remote unit calculates: (i) a first azimuth directionfor said first laser light transmitter, and (ii) a second azimuthdirection for said second laser light transmitter, which correspond tosaid known point of interest; (b) by use of a second command entered onsaid remote unit by said user, said remote unit commands said firstlaser light transmitter to slew in the azimuth so that said first laserlight plane becomes aimed at said first azimuth direction; (c) by use ofa third command entered on said remote unit by said user, said remoteunit commands said second laser light transmitter to slew in the azimuthso that said second laser light plane becomes aimed at said secondazimuth direction; and (d) after both laser light transmitters areproperly aimed, their respective first and second laser light planes nowintersect at said known point of interest and thereby provide a visualrepresentation at said known point of interest on said physical jobsitesurface.
 13. The system of claim 11, wherein: (a) said user selects anunknown point of interest on said physical jobsite surface; (b) bymanual control of said remote unit by said user, said first laser lighttransmitter is slewed in the azimuth until said first laser light planepasses over said unknown point of interest on said physical jobsitesurface; (c) by manual control of said remote unit by said user, saidsecond laser light transmitter is slewed in the azimuth until saidsecond laser light plane passes over said unknown point of interest onsaid physical jobsite surface, at which time said first and second laserlight planes provide a pair of visual lines that intersect at saidunknown point of interest on said physical jobsite surface; and (d) byuse of a fourth command entered on said remote unit by said user: (i)said remote unit communicates with said first laser light transmitter todetermine a first azimuth angle of said first laser light transmitterbased upon a first signal from said first azimuth position encoder; (ii)said remote unit communicates with said second laser light transmitterto determine a second azimuth angle of said second laser lighttransmitter based upon a second signal from said second azimuth positionencoder; and (iii) said remote unit performs a reverse calculation todetermine a set of coordinates for said unknown point of interest thatcorresponds to a coordinate system of said virtual floor plan, andthereby enters said unknown point of interest into said virtual floorplan.
 14. The system of claim 1, wherein: (a) said first base unitfurther comprises: a first laser receiver with a first null-positionphotosensor; (b) said second base unit further comprises: a second laserreceiver with a second null-position photosensor; (c) said first laserlight transmitter is controlled so as to aim said first laser lightplane at said second null-position photosensor; and (d) said secondlaser light transmitter is controlled so as to aim said second laserlight plane at said first null-position photosensor, therebyestablishing an alignment axis between said first and second base units.15. The system of claim 2, wherein: said intersecting first and secondvisual laser light lines indicate said visual representation at acorrect position for said virtual point along a horizontal direction,even if said physical jobsite surface is uneven.
 16. The system of claim10, wherein said remote unit further comprises: a display; and an inputsensing device that allows a user to enter commands to said remote unit;wherein said remote unit is configured: (a) to be in communication witha virtual floor plan; (b) to be in communication with said first baseunit and said second base unit; (c) to depict, on said display, at leasttwo benchmark points of said virtual floor plan; and (d) to depict, onsaid display, a known virtual point of said virtual floor plan that isto be plotted on a jobsite physical surface by said first laser lightplane and said second laser light plane.
 17. The system of claim 16,wherein said virtual floor plan is in communication with said remoteunit by way of at least one of: (a) said first base unit includes atransmitter circuit and a receiver circuit that communicates with aseparate computer that contains said virtual floor plan; and (b) saidfirst base unit includes a communications port that allows a portablememory device to be mounted on said port, and said portable memorydevice contains said virtual floor plan.
 18. The system of claim 16,wherein said remote unit communicates with said at least two base units,and sends signals to said at least two base units to command them to aimtheir laser light planes at predetermined azimuth angles so that saidknown virtual point is visually indicated by intersecting lines on saidjobsite physical surface.
 19. A base unit for use in a layout and pointtransfer system, said base unit comprising: a first laser lighttransmitter that emits a substantially planar vertical plane of laserlight in a static direction, said first laser light transmitter beingrotatable about a substantially vertical axis; a laser light receiverhaving: a null-position photosensor that is mounted to detect laserlight offsets in a substantially horizontal direction, and an amplifiercircuit interfacing between said null-position photosensor and saidlaser light receiver; and a leveling mechanism.
 20. The base unit ofclaim 19, wherein said first laser light transmitter comprises one of:(a) a fan beam laser light emitting unit; and (b) a rotating laser lightbeam emitting unit.
 21. The base unit of claim 19, wherein said levelingmechanism comprises one of: (a) a manual leveler unit having a pendulum;(b) a manual leveler unit having a bubble; and (c) an automatic gravitysensing leveler unit, that sends signals to a leveling motor drive. 22.The base unit of claim 19, wherein said null-position photosensorcomprises one of: (a) a split-cell photosensor; (b) a butt-cellphotosensor; (c) a light-conducting rod-style photosensor having twophotocells, one at each end of said light-conducting rod.
 23. The baseunit of claim 19, wherein said laser light receiver is configured: (a)to detect laser light from a second, separate laser light transmitter;(b) to determine an offset amount between said first laser lighttransmitter and said second laser light transmitter; and (c) tocharacterize said null-position photosensor to correct for said offsetamount.
 24. The base unit of claim 19, further comprising: a transmitterand a receiver for communicating signals with a remote unit that allowsa user to enter commands to said base unit.
 25. The base unit of claim19, further comprising: an angle encoder for automatic position sensingin an azimuth direction.
 26. The base unit of claim 19, furthercomprising: an azimuth motor drive for automatic control of an aimingposition of said first laser light transmitter.
 27. The base unit ofclaim 19, further comprising: a second photosensor with a cylinder lens,for providing gross position detecting capability.
 28. A method forsetting up a layout and point transfer system, said method comprising:(a) providing a first base unit which includes a first laser lighttransmitter that emits a first laser light plane; (b) providing a secondbase unit which includes a second laser light transmitter that emits asecond laser light plane; (c) positioning said first base unit and saidsecond base unit at two different locations on a solid surface of ajobsite; (d) determining an alignment axis between said first base unitand said second base unit; (e) aiming said first laser light transmitterat a first static direction and said second laser light transmitter at asecond static direction so that a first benchmark point is indicated byintersecting laser light lines along said solid surface, which areproduced by said first and second laser light planes; and determining afirst set of azimuth angles of said first and second laser lighttransmitters; (f) aiming said first laser light transmitter and saidsecond laser light transmitter so that a second benchmark point isindicated by intersecting laser light lines along said solid surface,which are produced by said first and second laser light planes; anddetermining a second set of azimuth angles of said first and secondlaser light transmitters; and (g) by use of said first and second setsof azimuth angles, determining positions of said first and second baseunits with respect to said first and second benchmark points.
 29. Themethod of claim 28, wherein a user is able to visibly see saidintersecting static laser light planes at said first benchmark point andat said second benchmark point.
 30. The method of claim 28, wherein saidstep of determining an alignment axis between said first and second baseunits comprises one of: (a) aiming said first laser light transmitter ata second reflector mounted to said second base unit, and aiming saidsecond laser light transmitter at a first reflector mounted to saidfirst base unit, thereby manually establishing said alignment axis; and(b) aiming said first laser light transmitter at a second null-positionlaser receiver mounted on said second base unit, and aiming said secondlaser light transmitter at a first null-position laser receiver mountedon said first base unit, and sending signals from said first and secondlaser receivers to a remote unit to command said first and second laserlight transmitters to individually slew their azimuth aiming positionsuntil reaching a null position for the opposite laser receiver, therebyautomatically establishing said alignment axis.
 31. The method of claim28, wherein said steps of determining said first and second sets ofazimuth angles comprises one of: (a) manually reading a first opticalangle scale mounted on said first base unit, and manually reading asecond optical angle scale mounted on said second base unit; and (b)automatically reading a first signal from a first angle encoder mountedon said first base unit, and automatically reading a second signal froma second angle encoder mounted on said second base unit.
 32. The methodof claim 28, for indicating a known point of interest, said methodcomprising the steps of: (a) providing a virtual jobsite floor plan inat least two dimensions; (b) providing a remote unit that includes amemory circuit, a display, and an input sensing device that allows auser to enter commands to said remote unit, said remote unit being incommunication with said virtual jobsite floor plan; (c) positioning saidfirst base unit and said second base unit at two different locations ona physical jobsite surface, and determining an alignment axistherebetween; (d) determining coordinates for two benchmark points ofsaid virtual jobsite floor plan, and determining azimuth angles of saidfirst and second laser light transmitters for each of said two benchmarkpoints, thereby registering positions of said first and second baseunits on said virtual jobsite floor plan; (e) selecting firstcoordinates for a first point of interest that was previously registeredin said virtual jobsite floor plan, and slewing said first and secondlaser light transmitters in an azimuth direction to aim at said firstcoordinates; and (f) visually determining said first point of interest,by indicating a location at which said first substantially verticallaser light plane and said second substantially vertical laser lightplane produce intersecting laser light lines on said physical jobsitesurface.
 33. The method of claim 32, wherein said step of providing avirtual jobsite floor plan comprises at least one of: (a) storing acomputer file in said memory circuit of said remote unit; (b) storing acomputer file in a portable memory device and mounting said portablememory device onto an input/output port of said remote unit; and (c)storing a computer file in a separate computer that is in communicationwith said remote unit by use of a communications circuit that exchangesdata between said remote unit and said separate computer.
 34. The methodof claim 32, wherein said step of slewing said first and second laserlight transmitters in an azimuth direction to aim at said firstcoordinates occurs by one of: (a) a manual aiming procedure, by usingazimuth angle scales on said first and second base units to aim saidfirst and second laser transmitters; and (b) an automatic aimingprocedure, by using azimuth motor drives and azimuth encoders on saidfirst and second base units to aim said first and second lasertransmitters.
 35. The method of claim 32, further comprising a step of:transferring said first point of interest to a ceiling surface byfinding a second location at which said first substantially verticallaser light plane and said second substantially vertical laser lightplane produce second intersecting laser light lines on said ceilingsurface, in which said second location is substantially vertically abovesaid first point of interest, with respect to gravity.
 36. The method ofclaim 35, further comprising a step of: creating an implied plumb linewith respect to gravity, wherein: (a) said implied plumb line existsbetween said first point of interest and said second location, and (b)if a substantially vertical solid surface is positioned proximal to saidfirst point of interest on said physical jobsite surface, then saidimplied plumb line is visible along the substantially vertical solidsurface.
 37. The method of claim 32, further comprising a step of:creating an implied plumb line with respect to gravity, wherein: (a)said implied plumb line exists above said first point of interest, and(b) if a substantially vertical solid surface is positioned proximal tosaid first point of interest on said physical jobsite surface, then saidimplied plumb line is visible along the substantially vertical solidsurface.
 38. The method of claim 28, for entering an unknown point ofinterest into a virtual floor plan, said method comprising the steps of:(a) providing a virtual jobsite floor plan in at least two dimensions;(b) providing a remote unit that includes a memory circuit, a display,and an input sensing device that allows a user to enter commands to saidremote unit, said remote unit being in communication with said virtualjobsite floor plan; (c) positioning said first base unit and said secondbase unit at two different locations on a physical jobsite surface, anddetermining an alignment axis therebetween; (d) determining coordinatesfor two benchmark points of said virtual jobsite floor plan, anddetermining azimuth angles of said first and second laser lighttransmitters for each of said two benchmark points, thereby registeringpositions of said first and second base units on said virtual jobsitefloor plan; (e) selecting an unknown physical point of interest on saidphysical jobsite surface, and slewing said first and second laser lighttransmitters in an azimuth direction to aim at said unknown physicalpoint of interest until said first substantially vertical laser lightplane and said second substantially vertical laser light plane produceintersecting laser light lines on said physical jobsite surface at saidunknown physical point of interest; (f) entering azimuth aiming anglesof said first and second laser light transmitters into said remote unit,thereby determining angular coordinates of said unknown physical pointof interest with respect to said first and second base units; and (g)using reverse calculations, plotting said unknown physical point ofinterest into said virtual jobsite floor plan, thereby registering saidunknown physical point of interest.
 39. The method of claim 38, whereinsaid step of providing a virtual jobsite floor plan comprises at leastone of: (a) storing a computer file in said memory circuit of saidremote unit; (b) storing a computer file in a portable memory device andmounting said portable memory device onto an input/output port of saidremote unit; and (c) storing a computer file in a separate computer thatis in communication with said remote unit by use of a communicationscircuit that exchanges data between said remote unit and said separatecomputer.
 40. The method of claim 38, wherein said step of slewing saidfirst and second laser light transmitters in an azimuth direction to aimat said unknown physical point of interest occurs by one of: (a)manually adjusting azimuth directions that said first and second lasertransmitters are emitting said first and second substantially verticallaser light planes until said first substantially vertical laser lightplane and said second substantially vertical laser light plane produceintersecting laser light lines on said physical jobsite surface at saidunknown physical point of interest, in that said user visuallydetermines when said intersecting laser light lines are correctlypositioned; and (b) entering commands at said remote unit, causingazimuth drive motors mounted in said first and second base units toadjust azimuth directions that said first and second laser transmittersare emitting said first and second substantially vertical laser lightplanes until said first substantially vertical laser light plane andsaid second substantially vertical laser light plane produceintersecting laser light lines on said physical jobsite surface at saidunknown physical point of interest, in that said user visuallydetermines when said intersecting laser light lines are correctlypositioned.
 41. The method of claim 38, further comprising a step of:before entering said azimuth aiming angles of said first and secondlaser light transmitters into said remote unit, determining said azimuthaiming angles of said first and second laser light transmitters by oneof: (a) manually taking visual readings, using azimuth angle scales onsaid first and second base units; and (b) automatically taking azimuthposition readings, using azimuth encoders on said first and second baseunits.